The pioneering Rance tidal power station near La Richardais is located on the estuary of the River Rance between Dinard and St Malo in Britanny. Construction began in July 1963 and it opened in November 1966. The dam, 163 m long, includes a lock measuring 65m X 13m which allows 20,000 vessels per year to pass between the river and the open sea. The power station is owned by Électricité de France (EDF), and has become a significant tourist attraction in the region. Visitors can see interactive displays illustrating various forms of renewable energy as well as examining the operations of the plant itself.